If the link is relevent to the site content, it has less likelihood of being paid. Also, many sites have advertising pages that mention paid link inclusion. You just have to know the ways around google
"Google" doesn't mind paid links at all when they are done for the right reasons. What they are trying to combat is paid links that are bought solely for the purposes of manipulating PR and SERP positions.
Google is against sites that using paid links to manipulate ranking in SERPs, yet there are some considerations with regards to sites with paid links that uses them for the benefit of visitors
"Google" doesn't mind paid links at all when they are done for the right reasons. What they are trying to combat is paid links that are bought solely for the purposes of manipulating PR and SERP positions.
Exactly, this is why they recommend the use of nofollow tag if you are selling paid links. However problem with that is, majority of the people wouldn’t buy links from you, if you mark them as nofollow.
since people want to rank their site in online especially in google organic listing some people in order to increase quality backlink they are going for buying link from quality page with high PR.